Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Method for suppressing direct voltage fluctuation of three-phase modular multilevel converter

A multi-level converter, three-phase module technology, applied in electrical components, output power conversion devices, etc., to achieve the effect of eliminating second harmonic current and preventing harm

Inactive Publication Date: 2013-07-10
ZHEJIANG UNIV
View PDF3 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problem of the second harmonic (double frequency fluctuation) of the DC bus voltage of the converter in the case of an AC system fault, the present invention provides a DC voltage fluctuation suppression method for a three-phase modular multilevel converter

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for suppressing direct voltage fluctuation of three-phase modular multilevel converter
  • Method for suppressing direct voltage fluctuation of three-phase modular multilevel converter
  • Method for suppressing direct voltage fluctuation of three-phase modular multilevel converter

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0022] The specific implementation of the present invention will be described in detail below in conjunction with the drawings and examples, but the present invention is not limited by the specific examples.

[0023] like figure 1 As shown, the three-phase modular multilevel converter consists of six bridge arms in three phases a, b, and c, and each phase has two upper and lower bridge arms. Each bridge arm 1 consists of a bridge arm series inductor L 0 It is formed by cascading with N submodules 2. The sub-modules SM1~SMN have the same structure, and each sub-module 2 consists of a first power electronic switch T 1 , the second power electronic switch T 2 (T 1 , T 2 Select a power electronic switch with self-shutoff capability, usually IGBT, IGCT, GTO, etc., this embodiment uses IGBT), a diode D connected in antiparallel with the first power electronic switch 1 , a diode D connected in antiparallel with the second power electronic switch 2 And the DC capacitor C consti...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a method for suppressing direct voltage fluctuation of a three-phase modular multilevel converter, which comprises the following steps of: utilizing detected converter bridge arm voltage to obtain a zero sequence voltage component in a phase unit through calculation; obtaining an additional control signal for suppressing double frequency fluctuation of direct current bus voltage through a band-pass filtering algorithm; subtracting the additional control signal from one half of a direct voltage value; superposing the additional control signal with an output voltage reference signal at the alternating current side of the existing converter to obtain a bridge arm voltage reference value; and carrying out pulse width modulation to obtain trigger impulse of each bridge arm of the converter so as to enable the converter to output corresponding voltage. Due to the adoption of the method for suppressing the direct voltage fluctuation, the second harmonic in the direct current bus voltage can be eliminated when asymmetrical fault occurs on an alternating current system, so that the second harmonic is prevented from inflowing to damage a converter at the opposite end.

Description

technical field [0001] The invention relates to the technical fields of flexible power transmission and distribution of power systems, power electronics and user power, and in particular to a method for suppressing DC voltage fluctuations of three-phase modular multilevel converters. Background technique [0002] Modular multilevel converter (MMC) is a multilevel converter topology that has attracted much attention in recent years. It uses multiple submodules (submodules, SM) cascaded, and by controlling the input and disconnection states of each submodule separately, it can make the AC voltage waveform output by the converter contain many voltage steps to approach the sine wave to the maximum extent. Thereby reducing the harmonic content in the output voltage and reducing the waveform distortion to meet the harmonic requirements of the power grid. [0003] The basic structure of a three-phase modular multilevel converter (such as figure 1 Shown) is composed of three-phase...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): H02M1/12
Inventor 徐政屠卿瑞薛英林唐庚
Owner ZHEJIANG UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com